How many batteries for fairly robust Wetsounds System?

[David Analog]

Ryan,
The way you have done your boat this time is totally fine. Absolutely zero wrong with it. However, just because you are using one method does not mean that it is the only way to go. If the charger amperage capacity is correctly matched with the battery reserve capacity and individual usage habits then there will be no issue either way. A mismatch will be an issue either way. What you did initially was probably wrong but for different reasons. It may have been a mismatch in capacity.
Here are some facts.
Many of the charger manufacturers clearly state on-line, in brochures, etc., that you can run more than one battery off of a single charger bank.
When in the industry, I have designed hundreds of marine audio systems, including far more complex systems in large boats. These methods work well. Problem free. Long lasting batteries.
Tournament fisherman often charge several trolling motor batteries off one charger bank. And these guys live and die by batteries. There is no alternator or stator connected to a trolling motor bank.
Motor yachts, valued at millions, charge more than one house battery off a single bank.
Powerful thrusters have their batteries driven off a single bank as original equipment.
You would have the OP believe that every one of these examples are wrong?

[CradGen2]

In my 2008 210 I had (4) Amps. 1000W Syn, (2) Syn 2s, (1) Syn 4. XXX sub, (2) Pro 485s, (6) XS650. I ran (3) Skurian 3200AH batteries for the system and (1) starting battery. That said my stereo was not hooked into my alternator. I use a Ctek to keep it charged. I run it pretty hard about 25 hour over a fri, sat, sun with 35-45 AMP draw and some 100Amp peaks. No issues.

In my new boat I have the same system, but do have the ability to charge off the motor. This time I put a amp switch bank in. Now I can turn the amps off then I'm hanging. Even the wildest party cover (1) pro485 is enough to kill anyone without a WS system. Also I like the fact I can cheat the WS420, but turning off the syn4 running the cockpit, but still get the sub running.

[nyryan2001]

David, I dont care if you did 10,000 installs. If you exceeded spec's on them they were all wrong, and why guys can't get batteries to last even when they have chargers. Under spec'ing as you rec voids the benefits of a smart charger, charges too slow, and can possibly burn up the charger. You have an under spec'd 6-9a charger per battery. Compartments in a wakeboat are 150degs for 6-8hrs after use as they share the same air as the engine and tranny when the charger is working its hardest. A fishing boat is separate areas, it'd be 50degs cooler on a fish boat. Bad comparison, apples and oranges. I learned the hard way listening to guys like you. Fail on a big weekend due to burnt up name brand charger For the wrong application(nearly the same you are rec to the OP) and low charged batteries.

Yes, the majority of 15a x2 chargers do say they can have 2 batteries on one bank. However NOT to exceed 200ahs. So your rec for his setup is 2 group 24s? You think that is adequate for what he has and how he plans to use it? He likely needs 4 24s or 3 29s to get into the A category for his situation.

A 60-80a x2 bank wouldn't be ideal for his setup either, too strong (for conditioning) on the single starter battery on the 1st bank. Other than my $350 rec, of taking a 15a x 4 bank and putting 3 of them on the Stereo side so it'd Get a full 45a, tell me a way to get him 600+ AHs on the stereo side, and get a charger on it all within spec.

I have 6 installs under my belt, but as an owner whose sole priority is to get it right the first time, lowest cost, and avoid fails.

[David Analog]

So Ryan, what was the specific make and model of charger you used and what exactly was your battery set-up details of the charging system of yours that failed?
What is the make and model of the charger you are using now with 3 + 1 Interstate group 29 flooded batteries?

[nyryan2001]

I had one side of a Prosport 20 on a 3 SRM29 stereo bank. 200ah capacity(per bank) trying to charge a roughly ~330ah battery bank, well beyond spec. It burnt thru the inline fuse and then damaged the internal charger power supply working overtime due to the intermitent fuse contact. I called them on it and they said ANY of their chargers would fail like that in an under spec'd scenario, and that warranty was voided and that they are able to detrmine exactly how it was misused in an application by the exact location and type of damage on the internal power supply. And it wasnt a "wow, we are surprised to hear this sorry for your troubles" it was a "youre a dummy" type conversation, that if I didnt understand the charging setups and how to get them within spec, I should leave that to professionals. And this one WAS installed by a professional. I was surprised to learn that "smart" chargers would allow themseleves to burn up whether it be from 150deg ambient compartment temps, being way under spec'd on a bank... or even power supply damage from a loose fuse trying to maintain proper amps. They blamed all 3 as the cause of failure.

Now I have a 4 bank Noco Genuis with 1 bank on a SRM29 starter(~110ahs on 220ahs rated charging capacity-50%) and the other 3 banks combined into 4 SRM29s for the stereo bank(~440ahs on 660ahs rated charging capacity- 66%). 120hrs on the boat this season, worked flawlessly, and I hammer my system. Longest hardest playtime for mine was probrably ~80% for 2-3hrs with the engine off while playing volleyball (~2800-3000w RMS at ~12.6v this last summer). When I was done, I started it off the stereo bank just to see if I could, no issues. The Genuis allows a few more mounting options being a sealed waterproof unit.

The point I am making is dont exceed or even approach max ah specs per bank...could lead to charger fails and lesser performance shortening battery life, it did for me on the same direction he was being pointed. I would even go so far as to install 2 separate chargers between the banks to get it right before I would go back to an under spec situation. A 3-4 bank Dual would be fine, but I wouldnt want to exceed 75% ah capacity on any one bank to really keep a premium charge/conditioning. From the size of the system he has, and how he plans to use it... I couldnt see him having less than ~300+ahs on the stereo side, unless he just really wants to hammer it and see how long they last. He may be ok with assuming a little risk to save weight, space and upfront battery costs, and a cheaper charger.

[David Analog]

Yeah, I totally get why the first scenario failed. The ProSport 20 is a cheaper entry-level charger. And it was clearly a mismatch for the application based on its own specifications. 300a/hs deeply cycled on a charger that has a max collective 20 amp capacity in a WET version that doesn't dissipate heat well was destined for failure. No one here was advocating such an application.